Decorative felted fibrous sheet



United States Patent DECORATIVE FELTED FIBROUS SHEET David A. Feigl In,Lancaster Township, Lancaster County, and oyd V. Hassel, East HempfieldTownship, Lancaster County, Pa., asslgnors to Armstrong ctlllk Company,Lancaster, Pa., a corporation of Pennsy vanla No Drawing. ApplicationMay 2, 1955 Serial No. 505,522

25 Claims. (Cl. 162-134) This invention relates generally to beatersaturated fibrous sheets, and more particularly to beater saturatedfelted fibrous sheets made from compositions containing syntheticelastomers. Still more particularly it relates to a method of producinga decorative pattern in sheets which have been beater saturated withsynthetic elastomers. It also relates to products so produced.

The known beater saturation technics have yielded many excellent fibroussheets. Yet if any one property has characterized sheets formed by meansof the beater saturation processes, it has been homogeneity. All suchsheets are outstanding in that a sheet presents a homogeneousappearance. This is true because the very purpose of the beatersaturation processes is to produce homogeneous sheets. The goal is tosymmetrically and evenly coat the individual fibers and then form thecoated individual fibers into a sheet. Thus a sheet made in a heatersaturation process does not present a distinctive, easily discernible,attractive pattern.

It is the primary object of the present invention to present such asheet. It is a further object of the present invention to present asheet made by the beater saturation process which possesses suflicientlyattractive appearance to be utilized as a surface covering without theneed for any further steps involving the application of decorativedesigns or patterns. Further objects and advantages will become apparentfrom the ensuing description.

Accordingly, the present invention contemplates forming an aqueousslurry containing sheet-making fibers. There is added to the slurry atacky synthetic rubber in amounts sufiicient to form coated fibers of atleast about 30% by weight of the rubber. The coated fibers are thenformed into clumps in a first suspension. The first suspension is thenadmixed with a second suspension of coated fibers having a colordifierent from that of the first suspension. The resulting mixture isthen formed into a sheet.

The fibers contemplated for use in the present invention may be any ofthose fibers known to be useful in the beater saturation process. Glassfibers, bleached semichemical pulp, purified cotton linters, raw cottonlinters, kraft fibers, wool, goat hair, rayon, nylon, and other similarfibers may be used. The selected fiber is formed into an aqueous slurryin accordance with known beater saturation technics. Usually the fiberswill comprise from about 0.5% to about 5% by weight of the slu l iiorder that the amount of rubber latex to be deposited on the fibers maybe controlled, the fibers may be pretreated prior to rubber addition byadding an electrolyte in the form of a salt of aluminum, ferric iron,stannic tin, or other polyvalent metal. The electrolyte may be added inthe form of a solid or as an aqueous solution. Examples of suitableelectrolytes are alum, aluminum chloride, aluminum sulfate, magnesiumchloride, magnesium sulfate, ferric chloride, ferric sulfate, stannicchloride, and stannic sulfate. Once the electrolyte has been PatentedSept. 22, 1959 dissolved, a suitable soluble hydroxide is added in orderto convert the metal ions to an insoluble state. Sodium hydroxide orammonium hydroxide are the preferred hydroxides to be utilized. Theinsoluble hydroxide serves to control the deposition of the rubber latexon the fiber coated with or containing the metal hydroxide.

This use of an electrolyte and a hydroxide to control deposition ofrubber latices is known in the art as the Pretzel process. Generallyspeaking, however, the amount of electrolyte to be added in the usualprocess will range from about 33 to about 60 parts by weight per 100parts by weight of dry latex solids. This amount is essential in orderthat the latex will deposit smoothly onto the fibers and in order thatit will not clump with itself or cause the clumping of fibers. In theprocess of the present invention, however, a smaller amount ofelectrolyte is added in order that the usually detrimental clumping maybe forced to take place. Thus it can be seen that the process of thepresent invention is opposed to the usual beater saturation process inthat it turns a normally detrimental situation into an advantage.Generally speaking, the amount of electrolyte to be utilized in thepresent invention as described will range from about 5 parts by weightto about 15 parts by weight per 100 parts by weight of dry latex solids.Different fibers and ditferent latices will cause some variation withinthe above range in the amount of electrolyte to be used in the presentinvention. However, with any given system, forming of the clumps callsfor substantially less electrolyte than that needed for the same systemin normal beater saturation processes. Usually the amount will beone-third to onehalf that normally used. Since this amount is usuallynot sufiicient to complete the precipitation, a precipitating solutionof alum sequestered with sodium citrate or its equivalent may be used tocomplete the process once the rubber has been added; this precipitatingsolution constitutes an aftertreatment made once the rubber has beenadded.

Following the solution of the electrolyte in the fibercontaining slurry,the hydroxide, preferably ammonium hydroxide, will be added as describedabove. The amount of hydroxide will be that equivalent to the metal ionsadded as the electrolyte, with a slight excess; this is obvious sincethe aim is to convert all the metallic ions to the insoluble hydroxide.Since the amount of electrolyte is substantially less than the amountnormally used, it can be seen that the amount of hydroxide also will becorrespondingly less than the amount normally used. Once the insolublehydroxide has been formed, tacky synthetic rubber is added to theslurry, preferably as a latex. Since it is essential in the presentinvention that the coated fibers be formed into clumps, an amount of therubber latex must be added which will accomplish the necessary clumping.It has been found that clumping will occur only when at least about 30%by weight of the coated fibers is made up of the tacky synthetic rubber.Thus the pick-up must be about 30% by weight based on the dry weight ofthe fibers. Although clumping will occur to some extent when the pick-upis at least about 30%, higher pick-ups are preferred. The pattern elfectachieved by the present invention is noticeable at 30% pick-up but itbecomes outstanding at about 50% pick-up. Thus it is a preferredembodiment of the present invention that the coated fibers contain atleast about 50% by weight of the rubber.

The rubber to be used in this invention may be any of a number of thosetacky synthetic rubbers well-known in the art. Typical of thesematerials are the products known as GR-S, which is a copolymer ofbutadiene and styrene containing about 50% to 70% butadiene; Hycar,"which is a copolymer of butadiene and acrylonitrile containing about 60%to butadiene; and certain of the neoprenes, which are polymers of2-chloro-butadiene- 1.3. If desired, homopolymers of butadiene may beemployed as well as homopolymers and/or copolymers of butadienehomologues such as isoprene. These materials can be genericallydescribed as synthetic rubber, and in particular they must possess theproperty known as tackiness. Since those synthetic products containingless than about 50% by weight butadiene are generally not tacky, theselatter materials are generally unsuitable in the present process.

Once the rubber latex has been added to the slurry, the fibers should beformed into clumps. It is this portion of the present process thatparticularly violates normal beater saturation technics. Where theproper amount of electrolyte has been used and where the proper quantityof rubber latex has been added as described above, clumps will readilyform on agitation. Where the amount of rubber deposited on the fibers isnear the lower limit necessary to form clumps, namely about 30% pick-up,agitation must not be unduly prolonged in order that the formed clumpsmay not be disrupted. Where, however, the amount of rubber deposited onthe fibers is of the preferred amount, namely 50% and up, it will befound that the clumps are surprisingly strong and can withstand a greatdeal of beating without being disrupted.

The above description has dealt with the forming of clump fibers solelyby the use of a pretreatment involving an electrolyte and hydroxideaddition. Alternatively, the electrolyte treatment may be omitted andinstead a precipitating solution may be added subsequent to the rubberaddition even in the absence of an electrolyte addition. Theprecipitaing solution may consist of acetic acid alone or a solution ofalum alone or a solution of alum. citric acid, or sodium citrate inwater. The precipitating solution containing a precipitating agent isadded in amounts sufficient to preci itate the rubber on the fibers andto form clumps. The precise amount of precipitating solution will dependon the type of fibers and on the amount of rubber being used in anyparticular case. If desired, use of the acidic precipitating solutionmay be coupled with the use of an electrolvte to obtain more precisecontrol over the clumping of fibers. Thus, in the present inventionclumps may be formed by pretreatment of the fibers with an electrolyte.by aftertreatment of the latex with a precipiating solution, or byvarious modifications involving both treatments.

Once the first suspension of clump fibers has been formed. the next steentails admixing the above-described first suspension with a secondsuspension of fibers having a color different from that of the firstsuspension. This color difference may be accomplished in several ways. Adyestutf or pigment may be incorporated into the slurry of the firstsuspension before clumping, or the dye or pigment may be incorporatedinto the slurry of coated fibers prepared by normal homogeneous beatersaturation processes. if desired, a series of suspensions eachcontaining clumped fibers may be prepared wherein each suspensionpossesses a different color. The clumped suspension may then be mixedprior to sheet formation. In similar manner, 1, 2, or more clumpedsuspensions may be admixed with a non-clumped suspension of fiberscoated in the usual way; the colors of the different suspensions may beadimted as desired. To put it another way, at least one suspension ofclumped fibers is admixed with at least one other suspension of clumpedor unclumped fibers wherein at least two of the mixed suspensionspossess different colors.

The final step in the process is the forming of the resultant mixtnreinto a sheet. The sheet is formed in a conventional way by feeding themixture to any paper-forming machine, such as a Fourdrinier, cylindermachine, wet machine, or the like, for felting into fibrous sheets.

It can be seen that a sheet made by the present process will possessinteresting decorative pattern or design effects.

There will always be a color contrast between at least one portion ofthe sheet resulting from clumped fibers and at least a portion of thebalance of the fiber: in the sheet. It should be apparent that sheetspossessing as many colors as desired may be prepared. Contrasting colorsmay be selected to achieve a predetermined effect on the viewer and asmany colors may be selected as desired. Additionally, the size of theclumps may be controlled to some extent both by controlling the amountof latex used and also the amount of electrolyte used in pretreatment.This allows to some degree the selection not only of the colors, but ofthe size of the color splashes that will appear in the final sheet.

Once the sheet has been formed on the conventional papermakingequipment, it need only be dried to be useful in certain applications asin wall coverings. Drying may be accomplished at room temperature or atelevated temperature in a suitable oven or stove, under a radiantheater, or on the conventional drum driers of a papermaking machine.

The product, however, maybe further treated in order to broaden itsuses. For example, if a floor covering material is desired, the densityand resistance of the product may be increased by subjecting it topressure, preferably at elevated temperatures. Should a long-wearingfloor covering be desired, a final facing, clear or colored, may be laidover the sheet of the present invention to serve as a wear surface. Sucha film, preferably of a vinyl polymer, may be hot pressed onto a surfaceof a sheet of the present invention, or it may be doctored or rolled onin the form of a liquid and subsequently cured at elevated temperature.The entire sheet may be cured with or without pressure.

If desired, the pattern sheet of the present invention may beimpregnated with a thermosetting resin and then cured at elevatedtemperatures under pressure to form an attractive surface coveringuseful in covering desks, counters, tables, and the like. It can readilybe seen that such a product will be highly resistant to water, alkali,acid, and the normal hazards of such applications, for example cigaretteburns. At the same time, the product preserves the pattern appearancebuilt into it by the beater saturation process.

The sheet formed by the present invention may also serve as a base uponwhich to print a wear-resistant decorative paint coat in accordance withknown procedures, using the built-in pattern as background. Even if thebuilt-in pattern is completely covered, the undersurface will preserveits recorative appearance, and the appearance may thus serve as a kindof trade-mark to identify the particular composition used or todistinguish between surface coverings whose wear surfaces presentsimilar appearances.

The following examples illustrate various embodiments of the presentinvention. All parts listed are by weight unless otherwise stated.

Example I Three sheets were prepared from the above three slurrles, eachsheet containing different amounts of the difierfent clumped fibers,namely, one-third red, one-third green; and 45% green; and 213696 green.

1) one-third black, (2) 10% black, 45% red, (3) 56%% black, 21%% red,and

Example II Three slurries were prepared using the following ingredientsand amounts:

lbergias Primuline Yellow- Bleached semiehemicai pulp Pontamine Scarlet"Purified cotton linters. Pontamine Grnen"- Alum, solution Ammoniumhydroxide, 28% solution.. GR-S N0. 2000, 38 o Alum-Citrate precipitatingsolution...

The precipitating solution was added after the rubber. It consisted of50 parts water, 5 parts alum, and 3 parts sodium citrate.

Three sheets were prepared, each containing an equal mixture ofone-third of the total weight of each of the slurries described above.Each of the 12" square sheets prepared as in Example I was subjected to300 pounds wet pressure.

Each sheet was saturated with a solution of Melmac 405" (thermosettingmelamine-formaldehyde resin) dissolved in a 50-50 mixture of water anddenatured alcohol. The percent pick-up for each of the three sheetsvaried between 31 and 51.5%.

Subsequent to the "Melmac 405" treatment, each sheet was maintainedunder a pressure of 600 pounds per square inch at a temperature of 305F. for a period of 10 minutes.

There resulted hard thin sheets having an acid and alkali resistantsurface, excellent tensile strength, and flexibility, while at the sametime possessing an attractive mottled appearance of three colors.

Example III Two slurries using the following ingredients in the amountslisted were prepared:

In each case the (SR-8 was precipitated by the addition of aprecipitating solution made up of 50 parts water, 5 parts alum, and 3parts sodium citrate.

Sheets were made up containing equal parts of the above two very clumpyslurries. Three sheets were prepared-one in which there was a minimum ofstirring, one in which the two slurries were combined and then stirredtogether for 5 minutes, and a third sheet in which the slurries werestirred separately for 5 minutes and then combined.

The three sheets all exhibited very similar appearances, thus showingthat the clumped fibers maintained the clumps even under vigorousagitating conditions. The three sheets were dried in an oven at 195 F.Similarly, three other sheets prepared as above were dried on a drumdrier having a surface temperature of 230' F.

Tough attractive sheets suitable for surface covering resulted in eachcase.

Example IV A clumped slurry of refined cotton linters containing 50%611-8 based on the dry weight of the fibers was pre pared as in ExampleIll, save the dye was omitted.

40 parts of raw cotton linters was combined with 0.3 part PontamineGreen BXN," 5 parts Sorapon SF" (a sodium alkylarylsulfonate wettingagent), 5 parts dry alum, followed by 2.6 parts ammonium hydroxide.

The undyed clumped refined cotton linters were mixed half and half withthe dispersed and uncoated raw cotton linters, dyed green, prepared asabove.

On drying, an excellent mottled sheet resulted.

Example V Two slurries were prepared using the following ingredients andamounts:

Ingredients No. 1 No, 2

Water 4, 000 4, 000 Refined cotton linters. 40 Raw cotton linters 40Pontnmlne Green BXN 0. 3 Alum l 6. 0 Sodium citrate l gg,s

amo .0 on-s III (mimi with 'lamol N) 7s. 0

weight of fiber) Example VI Two slurries were prepared having thefollowing ingredients:

Ingredients No. 1 No. 2

Water 12, 000 12, 000 Refined cotton iinters 120 Pontamlne Green EX 0. 9Alum (dry) 6.0 0. 0 Ammonia.--- 3.0 3.0 "Hyoar 1501" (40% solids) 150.21150. 2

In each case precipitation was done by a solution of 50 parts water, 5parts alum, and 3 parts sodium citrate.

Sheets formed from half and half mixtures of the above two clumpedslurries were strong and attractive in appearance.

Example VII Two slurries were made having the following ingredients:

Ingredients No. 1 N o. 2

Water 12,000 12, 000 Refined cotton linters. 120 120 Pontamlne GreenBXN" 0. 9 Alum 0. 0 6.0 Ammonia 3. 0 3.0 Neoprene (36%) l7l. 0 17!. 0

The neoprene was precipitated with a solution of 50 parts water, 5 partsalum, and 3 parts sodium citrate.

Sheets formed from half and half mixtures of the two slurries werestrong and possessed an attractive mottled appearance.

We claim:

l. The method of producing a decorative pattern m beater saturatedfibrous sheets which comprises forming an aqueous slurry containingsheet-making fibers, adding to said slurry sufficient tacky syntheticrubber to produce coated fibers of at least about 30% by weight of saidrubber, forming clumps of said coated fibers in a first suspension,admixing said first suspension with a second suspension of fibers havinga color ditferent from that of said first suspension, and forming theresulting mixture into a sheet.

2. The method of producing a decorative pattern in beater saturatedfibrous sheets which comprises forming an aqueous slurry containingsheet-making fibers, adding to said slurry sufficient tacky syntheticrubber to produce coated fibers of at least 30% by weight of saidrubber, adding to the resulting slurry an acidic precipitating solutionto form clumps of coated fibers in a first suspension, admixing saidfirst suspension with a second suspension of fibers having a colordifferent from that of said first suspension, and forming the resultingmixture into a sheet.

3. The method according to claim 2 wherein said precipitating solutioncomprises alum and sodium citrate.

4. The method according to claim 2 wherein said rubber comprises abutadiene-styrene copolymer containing at least about 50% butadiene.

5. The method of producing a decorative pattern in beater saturatedfibrous sheets which comprises forming an aqueous slurry containingsheet-making fibers, adding a water-soluble, polyvalent-metal,electrolyte salt to said slurry, converting said electrolyte to awater-insoluble hydroxide by reacting the same with a hydroxide, addingto the resulting slurry a tacky synthetic rubber in an amount sutficientto form coated fibers of at least 30% by weight of said rubber, adding aprecipitating solution to the resulting slurry to form clumps of coatedfibers in a first suspension, admixing said first suspension with asecond suspension of fibers having a color difi'erent from that of saidfirst suspension, and forming the resulting mixture into a sheet.

6. The method according to claim 5 wherein said electrolyte salt isalum.

7. The method according to claim 5 wherein said rubber comprises abutadiene-styrene copolymer containing at least about 50% butadiene.

8. The method of producing a decorative pattern in beater saturatedfibrous sheets which comprises forming an aqueous slurry containingsheet-making fibers, adding a water-soluble, poIyvalent-metal,electrolyte salt to said slurry in that amount sufficient to causeclumping of the fibers when coated with a rubber, converting said saltto a water-insoluble hydroxide by reacting the same with a hydroxide,adding to the resulting slurry a tacky synthetic rubber in amountsufiicient to form coated fibers of at least 30% by weight of saidrubber, forming the coated fibers into clumps in a first suspension,admixing said first suspension with a second suspenion of coated fibershaving a color different from that of said first suspension, and formingthe resulting mixture into a sheet.

9. The method according to claim 8 wherein said tacky synthetic rubbercomprises a butadiene-styrene copolymer containing at least about 50%butadiene.

10. The method according to claim 8 wherein said second suspensioncomprises clumped coated fibers.

11. The method according to claim 8 wherein said water-soluble saltcomprises alum.

12. The method according to claim 8 wherein said coated fibers compriseat least 50% by weight of said tacky synthetic rubber.

13. The method according to claim 8 wherein said sheet-making fiberscomprise cotton linters.

14. The method of producing a decorative pattern in beater saturatedfibrous sheets which comprises forming an aqueous slurry of cottonlinters, adding alum to said slurrry in an amount only suflicient tocause clumping of the fibers when coated with a rubber, converting thealum to a water-insoluble hydroxide by reacting the same with ammoniumhydroxide, adding to the resulting slurry a latex of a butadiene-styrenecopolymer containing at least about 50% butadiene in amounts sufiicientto form coated fibers of at least 30% by weight of said copolymer,forming the coated fibers into clumps in a first suspension, admixingsaid first suspension with a second suspension of coated fibers having acolor different from that of said first suspension, and forming theresulting mixture into a sheet.

15. The method according to claim 14 wherein said second suspensioncomprises clumped coated fibers.

16. The method of producing a decorative pattern in beater saturatedfibrous sheets which comprises forming an aqueous slurry containingsheet-making fibers, adding alum to said slurry in an amount of about1-6 parts by weight per parts by weight butadiene-styrene solidssubsequently added, adding sufiicient ammonium hydroxide to said slurryto convert said alum to an insoluble hydroxide, adding to the resultingslurry a latex of a butadiene-styrene copolymer containing at leastabout 50% butadiene in amounts sufiicient to form coated fibers of atleast 30% by weight of said copolymer, forming the coated fibers intoclumps in a first suspension, admixing said first suspension with asecond suspension of coated fibers having a color difierent from that ofsaid first suspension and forming the resulting mixture into a sheet.

17. The method of producing a decorative pattern in beater saturatedfiber sheets which comprises forming an aqueous slurry containingsheet-making fibers, adding to said slurry sufiicient tacky syntheticrubber to produce coated fibers of at least about 30% by weight of saidrubber, forming clumps of said coated fibers in a first suspension,admixing said first suspension with a second suspension of fibers havinga color difierent from that of said first suspension, forming theresulting mixture into a sheet, impregnating said sheet with a curableresin, and curing said resin at an elevated temperature.

18. The method according to claim 17 wherein said resin comprises amelamine-formaldehyde resin.

19. The method of producing a decorative pattern in beater saturatedfiber sheets which comprises forming an aqueous slurry containingsheet-making fibers, adding to said slurry sufiicieut tacky syntheticrubber to produce coated fibers of at least about 30% by weight of saidrubber, forming clumps of said coated fibers in a first suspension,admixing said first suspension with a second suspension of fibers havinga color difierent from that of said first suspension, forming theresulting mixture into a sheet, coating said sheet with a curablesynthetic resin, and curing said synthetic resin at elevated temperatureto form a wear-resistant layer on said sheet.

20. The method according to claim 19 wherein said curable syntheticresin comprises polyvinyl chloride.

21. A decorative felted fibrous sheet comprising clumps of coated fiberscoated with at least about 30% by weight synthetic rubber, said clumpshaving a color different sfi'lom at least a portion of the balance ofthe fibers in said eet.

22. A decorative felted fibrous sheet comprising clumps of coated fiberscoated with at least about 30% by weight synethetic rubber, caid clumpshaving a color different from the balance of the fibers in said sheet.

23. A decorative felted fibrous sheet comprising varicolored clumps ofcoated fibers coated with at least about 30% by weight synthetic rubber.

24. A decorative felted fibrous sheet comprising clumps of coated fiberscoated with at least about 30% by weight synthetic rubber, said clumpshaving a color dificrent from at least a portion of the balance of thefibers in said sheet, said sheet being impregnated with a curedsynthetic resin.

25. A decorative felted fibrous sheet comprising clumps References Citedin the file of this patent UNITED STATES PATENTS 2,322,887 Schwartz June29, 1943 2,375,245 Pretzel May 8, 1945 2,474,801 Owen June 28, 19492,613,190 Feigley Oct, 7, 1952 2,635,045 Bixler et a1 Apr. 14, 1953 10Horsey et al. Aug. 25, 1953 McQuiston Jan. 19, 1954 Kao Apr. 20, 1954Yundt Apr. 12, 1955 Hatcher Aug. 9, 195,5 Feigley Aug. 9, 1955 BaymillcrOct. 11, 1955 OTHER REFERENCES Technical Association of Pulp and PaperIndustry Journal (TAPPI), vol. 34, No. 1, January 1951, p. 46.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No.2,905,583 September 22, 1959 David A. Feigley, Jr., et al It is herebycertified that error appears in the printed specification of the abovenumbered patent requiring correction and that the said Letters Patentshould read as corrected below.

Column 4, line 4'7, for "recorative" read decorative line '72, for"differfent" read different column 5 line 57, in the table, third columnthereof, last item, for "158.0" read 158.l column 8, line 64, for"synethetic" read synthetic same line 64, for "caid" read said Signedand sealed this 5th day of April 1960.

(SEAL) Attest:

KARL H. AXLINE ROBERT C. WATSON Commissioner of Patents AttestingOfficer

8. THE METHOD OF PRODUCING A DECORATIVE PATTERN IN BEATER SATURATEDFIBROUS SHEETS COMPRISES FORMING AN AQUEOUS SLURRY CONTAININGSHEET-MAKING FIBERS, ADDING A WATER-SOLUBLE, POLYVALENT-METAL,ELECTROLYTE SALT TO SAID SLURRY IN THAT AMOUNT SUFFICIENT TO CAUSECLUMPING OF THE FIBERS WHEN COATED WITH A RUBBER, CONVERTING SAID SALTTO A WATER-INSOLUBLE HYDROXIDE BY REACTING THE SAME WITH A HYDROXIDE,ADDING TO THE RESULTING SLURRY A TACKY SYNTHETIC RUBBER IN AMOUNTSUFFICIENT TO FORM COATED FIBERS OF AT LEAST 30% BY WEIGHT OF SAIDRUBBER, FORMING THE COATED FIBERS INTO CLUMPS IN A FIRST SUSPENSION,ADMIXING SAID FIRST SUSPENSION WITH A SECOND SUSPENSION OF COATED FIBERSHAVING A COLOR DIFFERENT FROM THAT OF SAID FIRST SUSPENSION, AND FORMINGTHE RESULTANT MIXTURE INTO A SHEET.